Dolby Laboratories DP564, User Manual

Page: 82 / 101

DP564 Multichannel Audio Decoder Appendix A: Metadata
A-12
Extended BSI parameters translate seamlessly to decoders that read only universal
parameters.
A.5.1 Universal Parameters
Universal parameters are present in all Dolby Digital encoders and decoders.
Dialogue Level
The dialogue level parameter is discussed in Section A.2, Dialogue Level.
Channel Mode
This parameter (also known as
audio coding mode
) indicates the active channels
within the encoded bitstream and affects both the encoder and consumer decoder.
This parameter instructs the encoder as to which inputs to use for this particular
program; it tells the decoder what channels are present in this program so the decoder
can deliver the audio to the correct speakers.
The setting is described as X/Y, where X is the number of front channels (Left,
Center, Right) and Y the number of rear (surround) channels.
The availability of certain channel modes depends on the data rate and whether the
LFE Channel is present. For example, you can’t have a mono stream with an LFE
channel (1.1!) or a 3/2 stream at 96 kbps. Appropriate data rates are shown in the
definition of each setting.
Note : The presence of the LFE channel is indicated through a different metadata
parameter (see LFE Channel).
Channel
Mode
Setting
Definition and Data Rate
1+1
Dual mono (not valid for DTV
broadcast or DVD production)
1/0 Mono
From 56 kbps, usually 96 kpbs
2/0 Stereo
From 96 kbps, usually 192 kbps
3/0
From 256 kbps
2/1
From 256 kbps
3/1
From 320 kbps
2/2
From 320 kbps
3/2
From 384 kbps, often 448 kbps